The use of air pressure or vacuum to induce separation of kernels of grain from a bulk quantity is well known in the art. The use of a rotating drum with apertures is shown in U.S. Pat. Nos. 1,006,984; 3,156,201; 3,322,080; 3,542,242; 3,637,108; 3,731,842 and 3,762,603. The use of rotating discs in air or vacuum assist planters is shown in U.S. Pat. Nos. 1,046,199; 1,331,235; 2,991,909; 3,434,437 and 3,608,787.